Mulch is applied 2–4 inches thick around plants, trees, and garden beds. It reduces water evaporation by 25–50% and suppresses weed growth.
Types
- Hardwood bark: Long-lasting, attractive, decomposes slowly
- Pine straw: Acidifying, good for azaleas and blueberries
- Rubber mulch: Doesn't decompose, ideal for playgrounds
- Gravel/stone: Permanent, good for xeriscaping
How Much Do You Need?
Volume (ft³) = Area (ft²) × Depth (ft). 1 cubic yard covers 162 sq ft at 2" depth or 108 sq ft at 3" depth.
Mulch Volcanoes: A Common and Damaging Mistake
Piling mulch high against a tree trunk (a "mulch volcano") traps moisture against the bark, promoting rot and disease, and can encourage roots to grow up into the mulch layer instead of down — arborists universally recommend keeping mulch a few inches away from the trunk in a flat, donut-shaped ring instead.
Organic vs. Inorganic Mulch Lifespan
Organic mulches (bark, straw) break down and enrich soil over 1–3 years, requiring periodic replenishment, while inorganic mulches (rubber, gravel, stone) last indefinitely but don't improve soil health — the choice often comes down to whether the goal is soil improvement (organic) or low-maintenance permanence (inorganic).